The overall objective of this project is to examine principles of organization among populations of neurons and to devise means of recording the activity of populations of neurons. One such principle is that the independent components of the pattern of activity of a population of similar neurons are related to the physiological function of those neurons. Thus, among neurons of sensory systems, the features detected by the neurons at a given level would tend to be the independent components in the activity of the population of neurons which activate them. In motor systems, the independent components in the activity of a population of neurons would be an estimate of the signals that activate that population.